Laser Treatments Developed for Age-Related Vision Loss

Tests of laser treatments for AMD (Matti Ahlgren, Aalto University)

19 June 2019. Researchers in Finland are designing techniques using temperature-controlled lasers to treat a common form of vision loss associated with aging. The Macaluser project, led by a team at Aalto University in Otakaari, Finland, is supported by €900,000 ($US 1.01 million) in funding for development and commercialization by Business Finland.

The Aalto team led by neuroscience and engineering professor Ari Koskelainen is seeking better treatments for age-related macular degeneration, or AMD, a common disorder and the leading cause of vision loss in people over the age of 50. The condition occurs in the macula, the part of the retina with light-sensing cells at the back of the eye. When the macula is damaged, the retina’s ability to turn the sensed light into electrical signals for the brain is impaired.

The disorder usually begins with blurry or dark spots in the central vision view, and can progress at varying speeds, leading in some advanced cases to complete vision loss. About 90 percent of AMD cases are non-neovascular or “dry” AMD, since no leakage from blood vessels occurs. In late stages of dry AMD, large sections of the retina stop functioning, a condition called geographic atrophy.

Koskelainen and researcher Teemu Turunen are using lasers to treat AMD, by heating the light-sensitive cells in the back of the eye. “The causes of AMD include oxidative stress and the resulting protein misfolding and aggregation,” says Koskelainen in a university statement, “so we are developing a heat treatment for the back of the eye, which strengthens the defense mechanisms of retinal cells. These mechanisms help proteins refold back into their correct forms, and at the same time stimulate the natural healing process.”

While lasers are an established treatment option for diseases of the retina, they need to be carefully controlled to keep from overheating and damaging the targeted tissue. Turunen notes that “until now, it has not been possible to monitor the temperature of the retinal pigment epithelium while the treatment is administered. This is essential in order to avoid damage to the tissues being treated.”

The Macaluser technology uses a technique called an electroretinogram or ERG to monitor tissue temperature in the effective, but safe target range of 42 to 43 degrees Celsius (108 to 109 F). An ERG uses electrodes in a device similar to a contact lens that records electrical signals from the retina and relayed to a recording component worn on the forehead. Machine-learning algorithms are used to control the lasers and keep the heated tissue in the target range. Treatments last for about 1 minute and are expected to be given every few months.

The project team tested these techniques with lab animals to prove the concept, and are now conducting more preclinical tests of the process. The researchers are also packaging the technology in a single device, with clinical trials beginning next year. The Business Finland funding supports development of the treatment device, as well as its clinical trials.

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